I frequently have the problem where I get logged out on PC, log back in, and then any changes to my bookmarks I made while logged out end up getting erased and replaced with the older version from mobile which did not get logged out. I have to fix this by exporting my bookmarks before logging back in, deleting all of them once they sync to the old version, and then importing them again. This is very inconvenient, not to mention counterintuitive.
I think there should be a way to select which browser instance overrides the other when syncing happens.

@leocg in that case, what determines which overrides the other? is it just random, or is there a pattern?

I became logged out on desktop without realising, and did some re-organising of my favourites. On realising, I turned off sync on mobile, and logged back in on desktop, also with sync off.
How do I make it so that when I turn sync back on, the newer version of favourites from desktop replaces the older version on mobile, and not the other way around? When I've had this problem before, the older instance of the browser overrode the newer one.

I recently realised my opera web and opera mobile were out of sync, so I synced them. I'd recently started a lot of sorting of them on web, so I made a backup in case it synced the old ones from my phone to my computer instead of the other way around. That ended up happening, so I imported them from the html file.

The issue is, rather than replacing my current bookmarks, it just added a new folder containing the imported ones, with lots of nestled subfolders, rather than replaced my old bookmarks with the new imported ones. Is there a way I can clear all my bookmarks, and then import the new set not in a folder, or get it to replace rather than add a new folder when importing?

I tried deleting the bookmark files on my system, and the backups too, but when I open opera now it just stops responding for a minute, and they pop back immediately.